Imaging Device Phase Difference Detection Pixel Array Depth Estimation
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Solution Overview
Problem
Existing imaging devices face challenges in accurately determining depth maps due to phase differences between clock signals and light control signals, leading to inaccuracies in distance measurement and image quality.
Innovation Solution
The implementation of an imaging device with a pixel array comprising general pixels and phase difference detection pixels, where the phase difference detection pixels generate currents based on a switched charge source, allowing for data-driven adjustment of control signals to improve depth estimation accuracy by correcting phase differences between clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase difference detection pixels are added to the pixel array, then depth estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The pixel array is segmented into two functional types: general pixels for image capture and phase difference detection pixels for depth measurement. This segmentation allows the system to dedicate specific pixels to measuring phase differences between clock signals and light control signals, thereby improving depth estimation accuracy without requiring all pixels to perform both functions, which would increase overall complexity.
Solution Approach 2:
The phase difference detection pixels are designed to serve multiple purposes: they function as both image sensing pixels and depth measurement pixels. By making these pixels universal, the system avoids adding separate dedicated depth measurement components, thus improving depth estimation accuracy while minimizing the increase in device complexity.
2Adaptability or versatility
If phase difference detection pixels generate currents from switched charge sources, then control signal adjustment capability is improved, but manufacturing complexity increases
Solution Approach 1:
The phase difference detection pixels utilize parameter changes in the form of switched charge sources that can be controlled to generate currents. By adjusting the switching state and charge source parameters, the system achieves flexible control signal adjustment capability. This approach allows for adaptability in depth measurement while maintaining a relatively simple pixel circuit structure that can be manufactured using standard semiconductor fabrication processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the accuracy of depth estimation and improves the overall performance of the imaging device by compensating for phase differences, resulting in more precise distance measurements and improved image quality.
Implementation Method 1
a photodiode generating an electric charge in response to a received optical signal
Data Source
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AI summary
Disclosed in an imaging device which, in some examples, includes general pixels and phase difference detection pixels. The general pixels, when operated by control signals, receive light from a subject and generate currents or voltages that are measured; a depth is estimated based on the measurements. The phase difference detection pixels generate currents based on a switched charge source. Data obtained from the currents generated by the phase difference pixels is used to adjust the control signals and thereby improve an accuracy of the depth estimation. An image sensor 100 according to an embodiment includes a pixel array 110, a clock driver 120, a read-out circuit 130, an arithmetic circuit 140. The pixel array 110 includes a plurality of pixels 111 and 112 arranged in a row direction and a column direction. The pixel array 110 includes a plurality of general pixels 111 and a plurality of phase difference detection pixels 112. The general pixels 111 are arranged in an array form in the row direction and the column direction, and the phase difference detection pixels 112 are arranged in the row direction only. The number and arrangement of the phase difference detection pixels 112 may be variously changed. For example, the clock driver 120 may be connected to the plurality of pixels through a plurality of photo-control lines. The plurality of photo-control lines may be lines for inputting photo-control signals to each of the pixels. The read-out circuit 130 may be connected to the pixels through a plurality of column lines connected to selection transistors of the pixels. The phase difference detection pixels 112 have a structure, different from the general pixels 111. While a pixel circuit included in the phase difference detection pixel may have the same structure as a pixel circuit included in a general pixel, an electric charge circuit is connected to the pixel node, instead of a photodiode. As such, t he phase difference detection pixels are pixels which are configured not to detect light, for example by a light blocking layer which prevents or substantially reduces the received optical signal. A phase difference error may be detected that unintentionally appears between photo-control signals, or between a photo-control signal and a light control signal, and compensate for the phase difference error. Therefore, performance of the imaging device may be improved by increasing accuracy of data output by the pixels.